CHEMICAL AND HISTOLOGICAL-CHANGES CAUSED BY PRESSURE AND ENZYME TREATMENT FOR TENDERIZATION OF SPENT HEN MEAT

Spent 'White Leg Horn' hens were injected intravenously with papain (4 8 mg/kg live wt), 30 min prior to slaughter, and/or subjected to press ure treatment (14 kg/cm(2) for 1 h) at 20 degrees and 60 degrees C at pre- and post-rigor stages, respectively. Higher protein extractabilit y and collagen solubility were observed in treated samples. Enzyme tre atment mainly affected collagen solubility, while pressure treatment a ffected protein extractability. Electron micrographs revealed that pre ssure treatment mainly affected 'Z' lines, while digested pockets were evident in enzyme-treated samples. Sarcomere length increased signifi cantly (P<0.05) after different treatments at post-rigor stage, but no t at pre-rigor stage. Shear force value was the least in enzyme plus p ressure-treated samples, followed by enzyme, pressure and the control. Maximum tenderization could be achieved by synergistic effect of enzy me and pressure-treatment at post-rigor stage.